Threat Case

South American drug lords plan to kill the president in this implausible but tautly paced thriller. Hoping to avenge their losses in the U.S. ``war'' against drugs, the cocaine barons retain Jerry Sincavage, a stereotypically clinical assassin who had formerly worked for the CIA in Southeast Asia. But phone taps in Miami indicate their plot, and the Secret Service calls in Jack Gannon (last seen in Payback ). Gannon is a member of Delta Force, ``the U.S. Army's elite counterterrorist unit,'' and, it emerges, had served with the killer. Gradually, a trail of killings leads to Sincavage, who is traced to a Peruvian training base for guerrillas. Eluding a Delta Force raid, Sincavage arrives in New York City, where the president is due to address the U.N. All the while, a cocaine-dealing White House staffer, Steven Whitney Bradford, has been the barons' informant; apprehended with a briefcase full of coke, Bradford offers Gannon one last opportunity to nab his nemesis. With the possible exception of Bradford, none of Pollock's characters is three-dimensional, and the plot relies too heavily on coincidence. Nevertheless, devotees of armaments and assassinations will enjoy the technological revelry and bureaucratic maneuverings here. (June)